Re: Johnson motor with exhaust bypass

[jw-in-dixie]

quote wannabe outboard guy:

When you see an exhaust like that, or the long pipes seen on the racing motors used on hydros, are they separated inside the exhaust cover Isolating each cylinder? or is this open inside the exhaust cover both pipes getting exhaust from both cylinders?. I have seen some of these setups for Mercs on feebay and they are always big bucks. I would love to try and make one some cold winter day in my basement shop.

They can be either way. a real racing motor usually has aluminum blocks in the exhaust chamber to separate the flow from each cylinder. Most of the "look good" setups don’t have the blocks, in my experience.

If you try to make a set, think of chrome sink drain pipes, or tub grab bars. Both have 90 degree turns, saving you that struggle. It could be done by modifying the exhaust cover plate to accept this type of pipe. Not easy, but doable. 😉

I notice the pictured motor has a cable-operated open/shut valve, for quiet or noisy operation. 😎

Cheers, JW in Dixie